The present invention relates to improvements in apparatus designs used in upright vessels commonly called vertical shaft kilns (retorts) and particularly to apparatus to properly and uniformly distribute fluid therein.
Shaft kiln type of retorts are used in a number of industrial applications requiring the distribution of hot treatment fluids uniformly across the lateral extent of such units.
In one type of vertical treatment vessel, particulate material to be treated is fed into the top of the vessel and by releasing processed material from the bottom of the vessel the material is made to flow as a moving bed through the vessel in a gravity flow. Treatment fluid may be injected into various portions of the downwardly moving bed of material for contacting the particulate matter.
In various types of kilns, crushed material of a variety of sizes is treated with hot gases either formed by heating internally of the bed of material or by heating externally of the kiln and the hot gases are injected into the bed of material.
In all vertical vessels, including kilns, it is desirable and mandatory that all of the material in the kiln be subjected uniformly to the influence of the treating fluids.
It has been very difficult in the prior art to have a distribution system which will distribute the fluid uniformly across the lateral extent of the retort while offering minimum resistance and disturbance to the flow of solids through the retort.
Further, it is difficult to provide distribution apparatus which will provide the necessary distribution of fluids to enhance the thermal efficiency of the retort operation and yet which is easy to maintain or replace.
In the present system, in general, one or more distributor assemblies are used in retorts and the like wherein the solids gravity flow through the different reaction zones. The distributors are placed in retort vessels to uniformly distribute fluids into the broken solids to accomplish selected thermal and/or chemical reactions. Such reactions may be the drawing, gasification and/or the pyrolysis of coal, oil shale and the like. Multiple distributors are used to inject fluids uniformly across the extent of the solids bed as it moves through the retort vessel.
The present invention uses either one or a multiple of fluid distributors per level and one or more levels in a single vessel. In operational practice, the distributors are used to inject process fluids into beds of the moving solids to effect selected thermal treatment and/or chemical reactions.
The distributors each have a horizontal plenum formed by a protective metal shell. Fluids may enter the plenum at either or both ends and have unrestricted flow communication therethrough between the distributor ends. The distributors are supported at each end by, and protrude through, nozzles built into the vessel shell therefore supplying connections for external piping. Packing glands are provided at each end of the distributors to provide for their thermal expansion during high temperature operation.
The present invention contemplates full size distributors which are placed inside the retort on chords. Each has a rectangular channel with parallel vertical walls forming the lower portion of at least a length of the plenum, wall members having an inverted V-shape forming the upper portion of the plenum, the outer ends of the wall members being in vertical alignment with the vertical sides of the lower rectangular channel, L-shaped members slope inwardly to connect each wall member of the inverted V-shaped upper portion to the top of each vertical side forming the rectangular lower portion, the end of one leg of one of the L-shaped members being attached to a corresponding one of the inverted V-shaped wall members and the end of the other leg of one of the L-shaped members being attached to the top of the corresponding one of the vertical sides. Multiple orifices are formed in the leg of the L-shaped member attached to each of the wall members for coupling the interior of the plenum to the interior of the vessel for the distribution of fluid from the plenum to the vessel interior. These orifices control the fluids entry into the solids bed in the vessel. Each row of the orifices is recessed beneath the distributor inverted V upper portion to keep the orifices free of solids. The orifices are pointed downwardly at an angle to the distributor horizontal axis to provide better fluid distribution in the bed of solids. A half-section distributor is provided for the side walls of the vessel and utilizes a half inverted V-shaped upper portion and a half shape rectangular lower portion. Thus, the half-section distributor is a full sized distributor that is divided about the vertical axis.
Divergent nozzle type orifices with a larger outlet than inlet are used to minimize the fluid's pressure loss on flowing therethrough. Furthermore, the outlet dimension of each nozzle is sufficiently large to permit the smaller inlet dimension to be the flow controlling orifice. The plenum is designed for low pressure drop per unit length for fluid flow therethrough which simulates a plenum of infinite capacity thereby providing uniform fluid mass flow to each of the orifices. Therefore, in the present invention, the smaller orifice controls the injection of fluids into the bed solids. Thus the orifice sizes may be varied as needed to provide flow distribution uniformly across the lateral extent of the retort. The orifices may be either circular or slot type. The orifices are pointed downwardly under the inverted V to keep the solids, which flow around the distributor, from obstructing the orifices and to provide maximum penetration of the fluid into the solids bed.
Thus it is an object of the present invention to provide an improved fluid distributor for upright vessels commonly called vertical shaft kilns or retorts.
It is a further object of the present invention to provide improved distributors for kilns which properly and uniformly distribute fluid therein.
It is also an object of the present invention to provide an improved distributor which has, in crosssection, a larger vertical axis than horizontal axis.
It is still another object of the present invention to provide a distributor having a plurality of orifices of a size to provide fluid flow distribution uniformly across the elongated length of the distributor.
It is yet another object of the present invention to provide a distributor wherein the size of each orifice is selected to provide uniform mass fluid flow to all sections of the retort cross-section with the size of each orifice being designed to serve a selected retort cross-section and the orifice size compensating for changes in viscosity and density as the fluid flows along the inside axis of the distributor for fluid flow therethrough to simulate a plenum of infinite capacity thereby providing uniform fluid mass flow to all portions of the reaction zone in the retort bed of solids served by the distributor.
It is still another object of the present invention to provide supports in the wall of the vessel to retain each end of the distributor with means on each end of the distributor for engaging the wall support means so as to provide for thermal expansion during high temperature operation and also provide easy access and removal for maintenance or replacement.